<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <title>更新时的一个问题</title>
    <script src="../js/vue.js"></script>
</head>

<body>
    <h3>人员列表</h3>
    <div id="root">
        <button @click="updateMei">修改马冬梅的信息</button>
        <ul>
            <li v-for="p in persons" :key="p.id">
                {{p.name}}-{{p.age}}-{{p.sex}}
            </li>
        </ul>
    </div>

    <script>
        Vue.config.productionTip = false

        new Vue({
            el: '#root',
            data: {
                persons: [
                    { 'id': '001', name: '马冬梅', age: 19, sex: '女' },
                    { 'id': '002', name: '周冬雨', age: 18, sex: '女' },
                    { 'id': '003', name: '周杰伦', age: 21, sex: '男' },
                    { 'id': '004', name: '温兆伦', age: 22, sex: '男' }
                ]
            },
            methods: {
                updateMei() {
                    // 奏效
                    /* this.persons[0].name = '马老师'
                    this.persons[0].age = '50'
                    this.persons[0].sex = '男' */
                    // 不奏效
                    // this.persons[0] = {id: '001', name: '马老师', age: 50, sex: '男'}

                    // this.persons.splice(0,1,{id: '001', name: '马老师', age: 50, sex: '男'})

                    this.$set(this.persons, 0, { id: '001', name: '马老师', age: 50, sex: '男' })
                }
            },
        })
    </script>
</body>

</html>